Dressing mechanism



5 Sheets-Sheet l JNVENTOR.

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G. STEWART DRESSING MECHANISM `Ian. 4, 1949.

Filed Feb. A222%. 1945 Jan. 4, 1949. G. STEWQRT 2,453,444

` DRESSING* MECHANISM I v Filed Feb. 28, 1945 5 sheets-sheet 2 Jan. 4, 1949. G, STEWART 2,458,444

DRESSING MECHANISM y Filed Feb. 28, 1945 l 5 sheets-sheet 3 IN V EN TOR.

MMI www/qa `Jan. 4, 1949. v G STEWART 2,458,444

DRESS ING MECHANISM Filed Feb. 28, 1945 5 Sheets-Sheet 4 an if y I I X153 56?] 62 j? .4/ 67l/f? INVENTOR.

Jan. 4, 1949. G, STEWART 2,458,444

DRES S ING MECHANISM Filed Feb. 28, 1945 5 Sheets-Sheet 5 f//N W- I N V ENTOR.

Patented lJan. 4, 1949 2358.444 DRESSING Gilbert Stewart, Detroit, Mich.,v assigner `to Ex;-

Cell0 Corporation, Detroit, Mich., a, corporation of Michigan Application l'february 28, 1945, Serial No. 580,125

The present invention relates generally to improvements in dressing mechanisms 01' truing grinding wheels, and has particular reference to a new and improved dressing mechanism of .the type in which the dressing tool is `caused to describe forward and reverse movements,- `to dress oppositely extending surfaces of a form contour, such as that of a wheel for grinding V-shaped threads.

One of the objects of the present invention is to provide a novel dressing mechanism having a tool actuating means of 4 component kparts which is operable to translate the -t-ool in a dressing stroke across the abrading surface ofthe gri-nding wheel and simultaneously to move 'the tool reversibly from and toward the wheel axis-5to generate the wheel contour, andin which the strain and friction between the parts is mai-ntained in one relative direction throughout the stroke regardless of the reverse mover-ments of the tool, whereby,7 to obtain improved accuracy in the dressing operation,

A more speciiic object is to provide a new-and improved dressing mechanism which com-prises a dresser slide carrying the dressing'` tool and movable perpendicular-1y toward and 4from the grinding Wheel axis .under the control of a fixed templet complementary to the form of the contour to be produced, and anactuating slide supporting the dresser slide and mounted for reciprocation in a direction inclined to the wheel axis so that one component of movement is effective to translate the dresser slide in a dressing stroke along the axis, and in which the angle-of inclination of the actu-ating slide is so related vto the a form of the templet that the relative movement between the slideswill remain in the same direction throughout the stroke regardless of whether the dresser slide is moving toward or from the wheel axis.

Other objects and advantages will become apparen-t as the description proceeds.

In the accompanying drawings,

Figure l is a plan view of a dressing mechanism embodying the featuresof my invention.

Fig. 2- is a front end elevational viewof' rthe dressing mechanism.

Fig. 3 is a fragmentary rear end e l'evational View.

`Fig. 4 is a side elevational View.

Fig. 5 is a fragmentaryt-ransverse vertical seg,- -ticnal view taser-,1 approximately along See-5 cf; Eig-. l.

Fig.Y 6 is a fragmentary-planners :an en larged scale of the tool holding means.

9 Claims. (Cl. v1252---1'513 Fig. 'i is va fragmentary side elevational view of the tool holding means.

Fig. 8 -is a fragmentary horizontal sectional viewtaken along line 8-8 of Fig. 5.

Referring more particularly to the drawings,

the dressing mechanism constituting the exemplar-,v embodiment of the invention may he adapted for use on lvarious types of grinding -mechinesand -ior the purpose of dressing the surfacesof di-iferent forms of grinding wheels. In thepresent instance, :l have shown two grinding wheels G `mounted `in axially spaced relation on oneend of a grindingspindie. kL. and each having :a formed cutting contour with oppositely inclined side :flanks 2, and 3 and an arcuate periphery yIl.. Thus, the dressing mechanism' is shown with two dressing tools T, one for each wheel G, and is .operative to` cause each i001 to .describe thedesired wheel contour, The. dressing tool-sT are 4caused ,toginove as. asunt, and hence the. motion imparted by .the dressing mechanism is the someter. ,beth tools, and Vneed be described only increlazticn :to one grinding Wheel G and one associated tool 'IL 1t will -be understood that the contour `to, he ,produced need not be limited to the speciiicform shown. but can be varied as required for. dinerent purposes.`

The .dressing mechanism, in the particular ferr-n shown4 comprises a suitable base 5 which isi-adapted tc-be mounted in XcdypOStiOn aS by means of bolts 6 on a Suitable support 1 forming part ci v4a .grinding machine (not fully shown), and which may be located at either side of the `grund-ing wheel spindle l.. rIninstances where the front, of the grinding wheel G is arranged for grinding, vcontact with the work (not shown), the dressing mechanism preferably vis, located at the rear of` the wheel..

The base comprises .a plate having spaced parallel arcuate guides ,8 respectively at .opposite ends and-.supporting a .cradle .9 for angular ad- `i.nstment about an axis-substantially perpendicvier to. :the axis of the wheel spindle, l'. This adjustment is provided so'that the plane of movement `.of the dressing tool T may be inclined in accord-ance with the `inclination of the grinding wheel to compensatev for the thread lead when grinding4 screw threads. v,Suitalcile clamps l0 are provided on the front of the base 5 for securing the cradle 9 in position-of adjustment.

ivl'curiicd .on ,the tcp cit-he cradle 9. substana horiz. rit-a1 plane .for reciprocatcry at. an :angle toward and. from the axis spindle i en actcatino cr base slide H- -This slide in turn carries e dresser .slide l2 --fzcr tour is under the control of a xed cam, former or templ-et IS on the cradle 9. The c am I3 has a contour correlated to the wheel contour to be'v produced, and in instances, such as shown, where the wheel contour is generally Vshaped,the'camcontour is similarly shaped, and has oppositely inclined faces or surfaces I 4 and I5 connected by an intermediate circular fillet II 6.

The angle of inclination of the movement of'` the base or actuating slide I I to the spindle axis is dependent on the shape of the wheel contour. More particularly, this angle should be somewhat less than that of either wheel ank 2 or 3 and, hence, of either cam face I4 or I5, to the wheel radius in the dressing plane. In general,

' the inclination of the slide II should be less than that of any portion of the cam contourto a perpendicular to the spindle axis.

By reason of the smaller inclination of the slide I I, the relative movement between the two slidesV I I and I2 in traversing the dressing tool T across the grinding wheel-G will not be reversed for dressing the opposite wheel flanks 2 andS, but will be unidirectional. Consequently, friction versible power drive. In the present instance, the shaft 3| extends into a gear housing 32 mounted on the top of the central platform I9 of the cradle 9 and is connected through a train of gears to a worm gear 33 within the housing 32. The gear 33 meshes with a worm 34 on a shaft 35 journaled in and extending laterally from the housing. The outer end `of the shaft 35, in turn, is connected through a worm wheel 36 and worm --3'1 within a gear housing 38 to a shaft 39 driven u vby an electric motor 48.

witlithe cradle 9.

and strain between the slides are never reversed during dressing contact so that a high degree of accuracy is obtained.

The slides I I and I2 preferably have ball bearing supports. In the case of the base slide II,

the support comprises spaced parallel guide rails .540

I'I which are removably bolted or otherwise suitable secured to the top of elevated ribs I8 formed on a central plate portion or platform I9 of the cradle 9, and which are formed in `their remote or outermost sides with longitudinal V-shaped i5 guide grooves or races 20.' Two opposed guide bars 2i are bolted or otherwise suitably secured to the underside of the slide I I inside of longitudinal depending flanges 22, and are formed in their adjacent or innermost sid-es with longitudinal V-shaped guide grooves or races 23. YOne of the guide bars 2l is laterally adjustable by means of locating screws 24 to secureproper bearing engagement regardless of wear. A pluralityof balls 25, conned in carrier strips 26, are disposed in engagement respectively with the sets of opposed races 26 and 23 to complete the bearing relationship. Retainerv plates (not shown), bolted to the opposite ends of the rails I'I, extend outwardly across the ends of the ball raceways into the grooves 23 to confine the carrier strips 26. End plates 28 extend across and are bolted to opposite ends of the slide II to enclose the entire bearing support.

Any suitable means may be provided for reciprocating the slide I I. In the present instance, this means comprises a stationary nut 29 removably bolted or otherwise suitable secured to the underside of the base slide Il, and movably disposed in a longitudinal recess or grooveV 29a formed in the top of the platform I 9 between the ribs I8. The nut 29 is in threaded engagement 'with a lead screw 36 Von one end of a shaft 3I projecting outwardly through Vthe rearmost ,Y

plates 2l and 28 for connection to a suitable re- The motor 40 is of the reversible type and adapted to be controlled automatically by a limit switch 4I engageable by adjustably spaced dogs 42 and' 43 on one side of the slide II. In the present instance, the gear housing 38 and motor 48 are suitably mounted on a bracket 44 integral The dogs 42 and 43 are so adjusted that the switch 4I will be reversibly actuated automatically at opposite ends of the reciprocation of the slide I I.

The dresser slide I2 is similarly supported on the base slide II. More particularly, two guide rails 45 are bolted or otherwise suitably secured to the top of the slide l I in a position perpendicular to the axis of the wheel spindle I, and are formed intheir remote or outermost sides with longitudinal V-shaped guide grooves or races 46. Opposed guide bars 41 are bolted or otherwise suitably -secured to the underside of the slide I2, and are formed in their adjacent or innermost sides with longitudinal V-shaped guide grooves or races 48 in opposed relation to the races 46. The slide I2 is formed with depending longitudinal flanges 49 against the inner sides of which the bars 4l' are positioned. A series of balls 50, confined in carrier strips 5I are disposed in engagement with the sets of opposed races 46 and 48 to complete the bearing relationship. Retainer plates 52 are bolted to opposite ends of the rails 45 to conne the carrier strips in place, and end plates 53 on the opposite ends of the slide I2 serve to enclose the entire bearing support.

The slide 4I2-is normally urged in one direction, for'example rearwardly from the axis of the spindle I, by suitable spring means, and is adjustably or controllably constrained against such movement by the cam I3. In the present instance, this spring means comprises a rod 54 anchored at one end to the rear end plate 53 on the slide I2, and ext-ending longitudinally through the space between the guide rails 45 on the slide Il., A ycollar 55 is secured to the rod 53 intermediate its ends. A coiled compression spring 56 encircles the rod 53, and is seated at opposite ends respectively against a guide sleeve 53a abutting the front retainer plate 52 and the collar 55 prises two spaced upstanding brackets or standards 58 fixed on the top of the cradle 9 at opposite sides of the platform I8 and extending parallel to the slide II. A bridge plate 59 is bolted to the upper ends of the standards 58 and extends in vertically spaced relation over and across jth-eslide assembly. The plate 59 is formed with an opening 66 normally closed by a removable 4cover 6I, andthecam I3 is suitably bolted to the undersideof the cover in position Within the opening.

actuating slide having a ball bearing support on said base for reciprocation in a predetermined direction adapted to be disposed in inclined relation to the wheel axis, reversible drive means for translating said slide, a bridge on said base and having a cioss member extending over said slide, a dresser slide having a ball bearing support on said actuating slide for movement in a direction inclined to said iirst mentioned direction and adapted to be disposed in perpendicular relation to said wheel axis, a contour cam on said member and having a form with oppositely inclined sections and extending crosswise of said dresser slide, a follower on said dresser slide, spring means for vmaintaining said follower against said cam, and a dressing tool mounted on and movable with said dresser slide, the angle of inclination of said actuating slide being less than that of the similarly inclined section of said cam, whereby upon movement of said actuating slide in either direction the relative movement between said slides Will be maintained in one direction.

4. A grinding wheel dressing mechanism comprising, in combination, a supporting base member, an actuating slide mounted on said base member for reciprocation in a predetermined first path, a dresser slide member adapted to support a dressing tool and mounted on said actuating slide for movement in a predetermined second path acutely inclined to said rst path, a contour cam on one of said members and extending generally crosswise of said dresser slide, said cam having a contour with sections inclined oppositely with reference to said second path, the relative inclination between said paths being less than that of the contour section which is inclined in the same general direction, and a followei` on the other of said members constantly engaging said cam.

5. A grinding wheel dressing mechanism comprising, in combination, a supporting base, an actuating slide mounted on said base for reciprocation in a predetermined rst path, a bridge on said base and extending over said slide, a dresser slide adapted to support a dressing tool and mounted on said actuating slide for movement in a predetermined second path acutely inclined to said iirst path, a contour cam on said bridge and extending generally crosswise of said dresser slide, and a follower on said dresser slide constantly engaging said cam, the inclination to said second path to said rst path being slightly less than that of any similarly inclined portion of the form of said cam.

6. A dressing mechanism comprising, in combination, a supporting base, an actuating slide mounted for reciprocation on said base along a predetermined path and having a generally transverse component of movement in one direction inclined to said path and a generally longitudinal component of movement perpendicular to said transverse component, a dresser slide mounted at an angle on said actuating slide for movement therewith along said transverse component and for relative movement thereon along said longitudinal component, a contour cam fixed on said base and having a cam face extending transversely of said dresser slide and coacting therewith to determine the position of said dresser slide relative to said base along said longitudinal component at all points along said transverse component, said cam face including cam sections angularly inclined in opposite directions relative to the direction of said longitudinal component and at angles greater than or opposite to the angle of relative direction of movement of said slides so that upon movement of said actuating slide in either direction the relative movement of said slides along said longitudinal component will continue unidirectionally regardless of reversal of movement of said dresser slide relative to said base.

7. A dressing mechanism comprising, in combination, a base, an actuating slide reversibly slidable on said base, a dresser slide adapted to support a dressing tool and being reversibly slidable on said actuating slide, the directions of movement of said slides being relatively inclined at an acute angle, cam means for controlling the longitudinal movement of said dresser slide on said actuating slide while permitting movement of said dresser slide laterally with said actuating slide, all portions of the cam face of said cam means being inclined to the direction of movement of said dresser slide on said actuating slide at an angle greater than said acute angle.

8. A dressing mechanism comprising, in combination, a base, an actuating slide reversibly slidable on said base, a dresser slide adapted to support a dressing tool and being reversibly slidable on said actuating slide, the directions of movement of said slides being relatively inclined at an acute angle, cam means for controlling the longitudinal movement of said dresser slide on said actuating slide While permitting movement of said dresser slide laterally with said actuating slide, and two dressing tools mounted on one end of said dresser slide in laterally spaced relation for movement therewith, and being independently laterally adjustable thereon to vary their location and relative spacing.

9. A grinding wheel dressing mechanism comprising, in combination, a supporting base member, an actuating slide mounted on said base member for reciprocation in a predetermined direction adapted to be disposed in inclined relation to the wheel axis, means for translating said slide on said base member, a dresser slide member mounted on said actuating slide for movement in a direction inclined to said rst mentioned direction and adapted to be disposed in perpendicular relation to said Wheel axis, a contour cam on one of said members and having a form including oppositely inclined sections and extending crosswise of said dresser slide member, ar follower on the other of said members, and spring means for maintaining said follower against said cam, said dresser slide member being adapted to support a dressing tool for movementtherewith, the angle of inclination of said actuating slide being less than that of the similarly inclined section of said cam, whereby upon movement of said actuator slide in either one direction said dresser slide member will be reciprocated relative to said base member in accordance with the contour of said cam while maintaining relative movement to said actuating slide in one direction.

GILBERT STEWART.

REFERENCES CITED UNITED STATES PATENTS Name Date Bugbee July 13. 1926 Number 

